Inductors, transformers and other inductive components are commonly utilized in a wide variety of electronic circuitry, including in power supplies or DC/DC converters used to drive various electronic circuits, as illustrated in German Patent Publication DE 3,700,488 published Jul. 21, 1988. As time passes, there is a continued object to decrease both the cost and size of such electronic circuits. There is therefor a continuing objective to decrease the size and to increase the efficiency of such inductive components.
An important inductive component parameter is its height profile and it is a goal of inductive component designers to minimize this height profile. However, utilizing conventional techniques, it is difficult to decrease inductor size and still maintain the same component performance level. The total height of a circuit assembly including a circuit board or other substrate and the circuit components mounted thereon including the inductive component or components should be minimized to reduce total assembly height, desirably reducing overall assembly height.
Various types of inductors or inductive components are known and used in electronics. Each of these inductor types exhibits advantages and disadvantages. One type of known inductive component utilizes coated round copper wire for primary and any secondary windings. Since the round wire, when wound, has substantial air spaces in the windings and since these air spaces vary with how the wire is wound and with the tension of the wire, etc., these coated round wire inductive components are difficult to mass produce. Further, the air spaces between the windings reduce winding efficiency causing the inductive component to be relatively large for a given inductance.
A second type of inductive component proposes to employ an inductive winding formed of flat coated copper wire. Such an inductor or component can create a larger inductance value at a given current than a round wire inductor due to the increased conductor density caused by the elimination of much of the air space present between the coil windings of a round wire inductor. Accordingly, for a given inductance and current capacity, an inductive component formed of flat wire may have a lower height profile and handle a higher current due to the low resistance in the flat wire and its increased density. An example of such a flat wire inductive component is described in (German Patent Publication DE 4,007,614 published Sep. 13, 1990.
It has also been proposed to form inductive windings on printed circuit boards. Such a winding is formed as a conductive pattern using conventional printed circuit board manufacturing techniques. However, the printed circuit board is comprised mostly of insulation material which means that the copper printed windings must be small and the DC resistance of the winding is high, preventing the use of such coils in high current applications.
Despite past advances, there is a need for an inductive component for use in a power supply which has a high current primary winding usable for applications such as high current smoothing and a secondary winding, having an output current utilized to monitor the current and/or voltage in the primary winding and provide a supply voltage or information feedback to a control or other circuit connected thereto, without galvanic contact. There is also a need for an inductive component that can be mass produced easily and cheaply and that has increased performance.